A form is a structured document with one or more pages with fields to be completed. Typically, each field has an associated label or inscription stating the nature of the data the field should contain.
Two types of forms can be identified—fixed forms and flexible forms. A fixed form has the same positioning and number of fields on all of its copies and often has anchor elements (e.g. black squares or separator lines), A non-fixed or flexible form may have different number of fields which may be positioned differently from copy to copy. Examples of flexible forms include application forms, invoices, insurance forms, money order forms, business letters, etc.
Methods of structure assignment and document element search in an electronic graphical image are described in U.S. Pat. No. 5,416,849 but are limited to processing only fixed forms with no deviation in field arrangement.